As listeners will know, there exists a sub-species of New Zealander I call "the ferals".

They're a group of individuals lacking empathy, insight and intelligence and often subject, it seems, to the instinctive or impulsive action.

They are an untamed, untrained underclass that manage to combine transience, welfare dependence, criminal activity, violence – and a remarkable reliance upon alcohol and/or drugs. They distil all this into the feral lifestyle.

Ferals are disproportionately Maori but they are not exclusively so – there are feral Pakeha and Pacific Islanders too.

The fact so many ferals are also Maori deeply unsettles the politically correct and policy-makers. It seems there is something within the culture that creates them, other than socio-economic consideration.

They tend to neglect, hurt, maim and/or kill their kids. And ferals make up the vast number of persons with whom Child, Youth and Family have contact, but also our police, justice and corrections services. Nothing good has ever come of ferals, and nothing ever will.

Occasionally we sight them – usually in the dock at their arraignment or trial.

We were introduced to another of them this past week – Ngaire Tukiwaho.

Tukiwaho killed her baby. She is to serve just a little over two years for the manslaughter of her two-month-old son, Tahi. She had been drinking all day – baby in tow – became involved in a beating by her equally feral partner and then decided to go to sleep in the back of an adjacent car. She took the child with her and, in her drunken stupor, smothered baby Tahi to death. If anything, her backstory is even worse: every one of the five children she has had has either been removed or killed.

There have been many other Ngaire Tukiwahos in recent years: we have seen them either at their own trials or at those of their attendant partners. They are all of the same type: none are mothers worthy of the name. And, sadly, most are Maori.

All they do is breed. They do not mother. Their child was their meal ticket and a secondary consideration to just about everything else that happened in their lives. No, not secondary: remote and distant.

In an interview I conducted with Social Development Minister Paula Bennett last week, it was clear that this government has lost patience with the feral problem. And with any touchy-feely remedies. Not only have they been proven not to work, they have also wasted tens of millions of dollars encouraging the ferals to keep replicating themselves.

Which is ironic considering that Whanau Ora is the flagship of its coalition partner, the Maori Party. Most New Zealanders dismiss the policy and funding as the post-modern price of MMP, but it does have the capacity to save some Maori and low-income families, however, it will never save the ferals. They do not have the capacity to desire change, let alone to seek it. They like their lifestyle, which is why they cannot be allowed to parent and they must be henceforth restrained from doing so.

The only question is: how do we effectively stop the ferals from reproducing themselves? And that reply has only two possibilities – financial incentives or sterilisation.

Frankly, it should be the latter. A clear directive from the state that certain persons may not have children. That their behaviour, their IQ, their antisocial behaviour and their lack of empathy will harm the children they produce.

Incredibly, Ngaire Tukiwaho, who also lost a child to Sudden Infant Death Syndrome, is pregnant again, Bennett reported last week. None of the eight children that she and her partner have created are actually in the care of either of them. They have been proven unfit to parent but the state cannot stop them.

Our most extreme step is to have CYF in the delivery suite. The proper response should be compulsory sterilisation.

In fact, we have a responsibility to protect our society from the birth of these doomed children.

From the moment of conception, they are damned. Just being in Tukiwaho's womb condemns these children to feral status.

As a foetus they will be subject to a constant assault from alcohol, drugs, cigarette smoking and their mother's appalling disregard. They will become their parent.

How ironic, then, that we abort over 16,000 foetuses every year, but that too few of the ferals are among them.

The other alternative is to financially reward the ferals for not having kids. But the idea of shelling out sufficient money to ensure compulsory contraception or sterilisation seems risible. Hard-working, taxpaying Kiwis get nothing; the ferals get another free ride. As with the social welfare system, the perverse is enshrined.

No, the time has come. There are thousands of ferals who are unfit to ever parent. We know them – that information is readily available.